Light bars are mounted on the roof of vehicles, such as police, fire, or other emergency vehicles to provide warning lights. It is important that such warning light which may flash, rotate, or patterns are viewable over a wide angle. Such light bars are available from Star Headlight and Lantern Company of Avon, New York. When light sources, such as LEDs, are used in light bars, it is important that light from such light sources spread light outward from the light bar. Typically in light bars, such as prior art light bar 1 of FIG. 1, to use a parabolic reflector 2 behind LEDs 3 provided in banks. In this example, four parabolic reflectors 2a, 2b, 2c, and 2d are shown each reflecting LED light incident thereto. FIG. 2 shows the parabolic reflectors 2 apart from light bar 1. The parabolic reflectors 2 and LEDs 3 form the optical assembly of light bar 1. The parabolic reflectors 2 are mounted on a base 4 and collect and reflect light from their respective LEDs 3 that would otherwise not be emitted in the desired outward direction towards the light bar dome 5. Although useful, the reflected light in light bar 1 is limited in its viewing angle, and then illumination from the light bar may not have desired dispersion characteristics, such as in terms of uniformity or viewing angles of individual LED's. FIG. 3 shows the use of two optical assemblies of parabolic reflectors 2 and LEDs 3 along the left and right of a prior art light bar 1a, which like light bar 1 is mountable onto the roof of a vehicle.
Although lenses for controlling dispersion characteristics have been used in vehicle lamps, such as described in U.S. Pat. No. 5,373,430, such have not been used heretofore on light bars between illumination light sources and the outer light bar dome.